Currently, tablet making machines are known in which material to be compressed in powder or granular form, is supplied to the inner room of each matrix of a matrix assembly that is fixed peripherally to a rotary turret.
Each die matrix is entered, on opposing faces, by a pair of stamping heads which are secured to respective punches.
The punches of each pair of stamping heads are guided by respective coaxial holes made along the periphery of the rotary turret.
The punches are activated axially by suitable driving means, including e.g. cam means, which control the position of the punches upon rotation of the turret for each working cycle.
In particular, the Italian Patent Application No. 3514A/90, owned by the Applicant, describes a machine of the type as mentioned, in which there are means for coupling the stamping heads with the respective punches, and means provided in the punches for locking the coupling means.
The stamping heads are secured to, or released from, the punches by tightening or releasing the locking means.
The above mentioned locking means include a screw member that passes through a transverse hole made in the respective punch and that engages wedging means made in form of a wedge that enters an indentation made in the stamping head.
The compressing device has achieved good results, and in particular allows for quick and easy change over of the heads, so that tablets with different sizes can be produced.
However, the rigid locking of the coupling means with respect to the punches may bring about damaging stress.
For example, the coupling means may be displaced while engaging the stamping heads, and the displacement would also concern the locking means.